1. Field of the Invention
The present invention relates to porous implants and, in particular, to an implant with a porous material mounted on a core.
2. Description of the Related Art
Dental implants are commonly used to anchor dental restorations or prosthetic teeth at one or more edentulous sites in a patient's dentition at which the patient's original teeth have been lost or damaged. The dental implant is typically threaded or press-fit into a bore which is drilled into the patient's mandible or maxilla at the edentulous site. Typically, a dental implant device is provided in one or two pieces. For a two piece device, an anchoring member or implant supports a separate coronal dental abutment, which in turn provides an interface between the implant and a dental restoration. For a one piece integral device, the device has an abutment section coronal to an implant section of the device. In either case, the restoration is typically a porcelain crown fashioned according to known methods.
For a two-piece device, there are two-stage surgery implants (also called endosseous implants) that only rise to the crest of the mandible or maxilla. In this case, the surgery is often performed in two stages. In the initial stage, an incision is made in the patient's gingiva at an edentulous side, and a bore is drilled into the patient's mandible or maxilla at the edentulous site, followed by threading or impacting a dental implant into the bore using a suitable driver. Thereafter, a cap is fitted onto the implant to close the abutment coupling structure of the implant, and the gingiva is sutured over the implant. Over a period of several months, the patient's jaw bone grows around the implant to securely anchor the implant in the surrounding bone, a process known as osseointegration.
In a second stage of the procedure following osseointegration, the dentist reopens the gingiva at the implant site and secures an abutment and optionally, a temporary prosthesis or temporary healing member, to the implant. Then, a suitable permanent prosthesis or crown is fashioned, such as from one or more impressions taken of the abutment and the surrounding gingival tissue and dentition. The temporary prosthesis or healing member is removed and replaced with the permanent prosthesis, which is attached to the abutment with cement or with a fastener, for example.
Alternatively, a one-stage surgery, two-piece implant, also called a transgingival implant, is placed in a single stage because it extends through the gingiva for attachment to an abutment. The one-piece implant also is placed in the jaw in a single stage.
Although the osseointegration of existing dental implants into surrounding bone has proven adequate, further improvements in osseointegration of dental implants are desired. For example, patients would prefer the shortest healing time from surgery to the time the implant can be fully impacted by occlusal forces. Also, a desire exists to provide strongly osseointegrated implants for high risk patients, such as smokers, diabetics and/or abnormally slow bone growth.